Pet food supplement



FIG. 1 is a perspective view of a pet food supplement embodying the new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof; and,

FIG. 4 is a left side view thereof and is identical to a right side view thereof.

The broken lines shown in the drawings illustrate unclaimed portions of the pet food supplement and form no part of the claimed design. 

The ornamental design for a pet food supplement, as shown and described. 